[creepingcharlie]

I a ford e150 in my shop and it came in for over heating when driving with the ac on. we could get to over heat for half the day. Then when i was driving it got hot light came on and started to run like crap. so i replace the t stat thought it might be stick close. after about two days the customer comes back saying its doing it again. what dose any think it might be? I thinking it might be the radiator. thank for any help.